They have celebrated each of their 50 goals by performing sujood, the Islamic act of prostration.

And Muslims observe Ramadan by fasting from dawn until dusk. No food or no liquid is consumed from dawn (Suhur) to dusk (Iftar) in order to cleanse the soul and mind.

It is a practice which was branded "totally irresponsible" by Dutch physio Raymond Verheijen this week, after the Dutch club had three players, Noussair Mazraoui, Hakim Ziyech and Zakaria Labyad all due to fast on the day of Ajax's Champions League semi-final 2nd leg against Tottenham.

In an interview with De Telegraaf ahead of the 2nd leg he said: "It would be totally irresponsible to comply with Ramadan at this time of the season.

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"Imagine that the game ends 0-1 and, after 90 minutes, they have to play an extension, I hope that the players themselves think that will be impossible."

Morocco international Mazraoui, however, who played the full 90 minutes of Ajax's dramatic 3-2 defeat on Wednesday, believed it wasn't an issue.

"I am used to doing it. Can a high-level athlete stop eating if he has to make a big effort? There are different opinions, but this is my choice, I feel quite energetic during Ramadan,” Mazraoui said in an interview with the Het Parool newspaper.

If the fast is strictly followed, the Moroccan defender would not have consumed any food or liquid from 6am to 9.15pm – 15 minutes after kick off at the Amsterdam Arena.

“The game is at 9pm (CET), so at 9.15 pm I would have the chance to drink something, if I play, I can go quickly to the band to take a sip,” he added.

Ajax players were seen consuming energy gels and drinks during a break in play at the Amsterdam Arena.

The same issue was raised ahead of Liverpool's Champions League final against Real Madrid last season, which also took place during Ramadan.

Manager Jurgen Klopp insisted it was a private matter for Salah and Mane.

"Religion is private, how I understand it," he said in his pre-match press conference. "Nothing to say about that but all fine, you will see him out there. In training he is full of power - you need to be the day before a final."

It is believed that Salah did not fast, but was still able to follow the precepts of his religion.

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But while fasting is obligatory for adult Muslims, those who are suffering from illness, travelling, elderly, pregnant, breastfeeding, menstruating or chronically ill are exempt.

Athletes and those who participate in physically demanding sports are also exempt from fasting on matchdays.

Under Islamic teachings, it is allowed to break or postpone your fast “with anything that is an adequate need” in order to preserve one's health, which is why Salah did not fast during last season's Champions League final and was not considered a less devout Muslim as a result.

This summer's 2019 Africa Cup of Nations has already been pushed back a week to commemorate African Muslim players who fast, allowing players to rest after Ramadan. The tournament was originally going to begin on June 14, but will now commence on June 21 and conclude on July 19.